This invention relates to new and useful improvements in saw chain holding mechanisms for grinding machines.
Many saw chain grinding machines employ a chain holding bar or plate on which the chain is mounted for engagement by a grinding wheel. These bars have a longitudinal edge slot that receives the drive tines of the chain in slidable guided engagement. The drive tines frequently become damaged or misaligned on the chain, and for this purpose the slot in the chain holding bar is intentionally manufactured with side play for the tines so that they will readily slide along the groove when adjusting the chain along the bar.
In order to anchor the chain for holding it in a fixed position when engaged by the grinding wheel, prior saw chain grinding machines have chain stabilizing means in association with the chain holding bar. For example, U.S. Pat. No. 3,349,645 provides a saw chain grinding machine with a combination of stop pawl that hooks behind the cutter elements to hold them against retracting movement with relation to longitudinal forces when engaged by the grinding wheel, a hold-down lever securing cutter elements being ground against vertical movement, and a stabilizing anvil on the opposite side of the cutter element being ground from the hold-down lever for stabilizing the cutter elements against lateral forces imparted to them by the grinder. Similarly, U.S. Reissue Pat. No. 28057 provides a stop pawl, a hold-down lever, and a stabilizing anvil.
With these prior structures the cutter elements tend to assume different upright anchored positions relative to other of the cutter elements on the chain since even with the operation of a stop pawl, a hold-down lever and a stabilizing anvil, the drive tines may assume varied upright positions in the bar slot. This causes a non-uniform grind of the cutting edges and corners of the chain and an efficient grinding function is not achieved.